I cannot switch my mouse to left-handed use, because the corresponding option in Gnome Control Center doesn't work since the upgrade from Gnome 3.18 to 3.28. I set Primary button to 'Right' and it's not applied.
At the moment I use xmodmap -e "pointer = 3 2 1" to swap buttons. It works.
It works in Gnome 3.38 at the moment.